I. Field of the Invention
The present invention relates generally to a tube end fitting and, more particularly, to a butt-weld, beam seal type fitting with a retained or captured coupling nut. The preferred fitting or fitting assembly is an improvement over the prior art fittings due to a significant savings in weight and in the improved function of the coupling nut. This improvement is a result of the virtually true concentricity and perpendicularity of the coupling nut versus the compromised geometry inherent in the conventional stake-on wire retained nut. The present fitting provides a nut that is precisely positioned to protect the seal face of the fitting, yet exposes just the minimum amount to permit easy mating with the sealing surface of the mated fitting. The capture ring provides these benefits as well as simplifying the manufacturing procedures required to fabricate the retained nut fitting.
II. Description of the Prior Art
U.S. Pat. No. 2,417,350 to C. L. Conroy entitled Method Of Manufacture Of An Adaptor Union, is directed to an adaptor unit that includes a swivel nut, and a body having an integral spud. The swivel nut includes a flanged end, an internal annular recess and threaded interior portion, while the body includes a conical head and restricted neck. The flanged end of the swivel nut engages the restricted neck of the body. This patent fails to provide a threaded nut having a flange that fits about the outwardly flanged end of a capture ring.
U.S. Pat. No. 2,460,110 to L. M. Stinchcomb, et al. entitled Coupling Means, is directed to a separable hose coupling made of metal. The coupling includes a male half having a rounded tubular nipple and an expanded, externally threaded end, and a female half having a rounded tubular nipple with a flange. An internally threaded nut is mounted on nipple and the nut has an inturned flange adapted to engage the nipple behind the flange. A rib is placed on the female half but spaced from the flange so that the inturned flange is positioned between the rib and the flange. When the female half is forced into the end of a hose, the inturned flange of the nut will move against the rib. When the hose is fully in place, the nut will be loose between the end of the hose and the flange of the nipple. This patent does illustrate, albeit for a hose coupling, movement of a secured threaded nut on a sleeve or tube but for a hose coupling. It does not, however, provide the retention ring structure of the claimed present invention that permits one to adjust, as desired, pullback position of the nut.
U.S. Pat. No. 4,877,270 to E. D. Phillips entitled Connector For Tapered Glass Joints, provides several forms of a joint connection. The joint connection includes a first glass tubing section having a tapered inner end surface and an outer surface with a threaded portion, a second glass tubing section having an outwardly flared end and an outer circumferential groove, a replaceable sleeve having a tapered outer surface adapted to mate with the taper surface, a retaining ring, and a cap having a dependent skirt with internal threads that are adapted to be threaded onto the threads of the outer surface. In use, the ring is slipped over the end of the second tubing section and into the groove. The cap is then moved axially on top of the end of the second tubing section into engagement with the ring, and the sleeve is positioned over the flared end and against the underside of the cap. The first tubing section and the cap are threaded tightly to force the tapered outer surface into sealing engagement with tapered surface. The present fitting assembly does not have the two tubing sections or a separate retaining ring and a skirted cap.
U.S. Pat. No. 4,073,512 to D. R. Vian, et al. entitled Quick connect Device For Auto Radiators, is directed to a device for connecting an auxiliary cooler to an existing automobile. The device includes a hollow tube having flared ends, and an adaptor coupling that includes a bore so that the tube is slidably received therein. The adaptor coupling has a threaded portion and an adjacent hex-sided portion.
U.S. Pat. No. 3,572,775 to J. Bloom, et al. entitled Brazed Fittings is directed to an improved sleeve that is to be joined to metal tubing by brazing or welding.
None of these patents provides the uniquely structured fitting assembly of the present application.